A development of the system for analysing X-ray whole-powder-data without using a structural model

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The system for analyzing X-ray powder diffraction data has been developed. Is is based on the procedure developed for analyzing neutron powder diffraction data by G.S.Pawley (J.Appl.Cryst.,14,357-361,1981).The procedure has been applied to the data analysis in X-ray powder diffraction.The system can decompose overlapping reflections into individual ones,and give integrated intensities and individual profile shapes as a function of diffraction angle. It can further refine unit cell parameters.The analysis can be performed without using a structural model.Thus structural knowledges are not required for system users.If the sample contains a internal standard material,the peak shift due to instrumental and specimen causes can be corrected automatically during the profile refinement.During 2 years of the research project,1) the system was designed,2)the profile model for X-ray powder diffraction data has been developed,3) the computer program was written Fortran statements,and 4)the system was tested for various samples.The system demonstrated that1)it has a high resolving power for decomposing overlapping reflections compared to the convevtional profile fitting technique,2) it has high cost-performance since the whole powder pattern is refined automatically, and 3)it can provied high accuracy in refined parameters. The future system should be improved in some respects;1) a further improvement of automation of analysis,and 2) toughening against the bad conditioning of the least squares refinement.